Patent Document 1 discloses an optical fiber containing an optical glass fiber having a core and a cladding and a resinous coating layer covering the periphery of the optical glass fiber, in which the resinous coating layer is formed so as to have a three-layer structure composed of a primary layer of a two-layer structure and a secondary layer disposed on the periphery of the primary layer in order to improve tensile strength of the optical fiber.
Patent Document 1: JP-A-2012-136401